package com.myimooc.security.rsa;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

/**
 * RSA非对称加密演示
 * Created by ZC on 2017/4/12.
 */
public class DemoRSA {

    /** 待加密字符串 */
    private static String src="imooc security rsa";

    public static void main(String[] args){
        jdkRSA();
    }

    public static void jdkRSA(){
        try{
            // 1.初始化密钥
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
            keyPairGenerator.initialize(512);
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
            RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
            RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();

            // 2.私钥加密、公钥解密：加密
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE,privateKey);
            byte[] result = cipher.doFinal(src.getBytes());
            System.out.println("私钥加密、公钥解密：加密:"+ Base64.encodeBase64String(result));

            // 3.私钥加密、公钥解密：解密
            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
            keyFactory = KeyFactory.getInstance("RSA");
            PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            cipher.init(Cipher.DECRYPT_MODE,publicKey);
            result = cipher.doFinal(result);
            System.out.println("私钥加密、公钥解密：解密:"+ new String(result));

            // 4.公钥加密、私钥解密：加密
            x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
            keyFactory = KeyFactory.getInstance("RSA");
            publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            cipher.init(Cipher.ENCRYPT_MODE,publicKey);
            result = cipher.doFinal(src.getBytes());
            System.out.println("公钥加密、私钥解密：加密:"+ Base64.encodeBase64String(result));

            // 5.公钥加密、私钥解密：解密
            pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
            keyFactory = KeyFactory.getInstance("RSA");
            privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE,privateKey);
            result = cipher.doFinal(result);
            System.out.println("公钥加密、私钥解密：解密:"+ new String(result));

        }catch (Exception e){
            e.printStackTrace();
        }
    }

}
